Since the investigators are looking for the highest tolerable dose of the study drug, bevacizumab, that can be administered safely without severe or unmanageable side effects in participants that have sarcoma, not everyone who participates in this research study will receive the same dose of the study drug. The dose patients get will depend on the number of participants who have been enrolled in the study and how well they have tolerated their doses. The dose of doxorubicin and radiation therapy will be the same for all subjects throughout the study.